Aircraft anti-icing apparatus

ABSTRACT

Anti-icing/de-icing apparatus for use in aircraft, comprising apertured fairings constructed from aluminum or alloys thereof defining air spaces therewithin, and means for delivering temperature controlled warm air under pressure to said air spaces, which means includes a conduit for conveying engine bleed air to said air spaces, an inlet to the conduit for cool ambient air to be mixed with the relatively warm engine bleed air, an anti-icing valve interposed in the conduit between the engine bleed air intake and the ambient air inlet and control means for regulating the valve to maintain the pressure and temperature of the air delivered to the air spaces below predetermined nominal values, said control means including pressure-responsive means and manually-controlled electrical means for overriding the pressure-responsive means. Additionally, the present invention contemplates an emergency relief valve disposed in the conduit downstream of the ambient air inlet and adapted to open in the event that the pressure or temperature of the air passing thereby is of greater than a predetermined maximum value.

United States Patent [191 Christensen et al.

[ 1 July 31, 1973 AIRCRAFT ANTI-ICING APPARATUS 73] Assignee:Midland-Ross Corporation,

Cleveland, Ohio [22] Filed: Mar. 10, 1972 [21] Appl. No.: 233,573

Related US. Application Data [63] Continuation-impart of Ser. No.885,503, Dec. 16,

I969, abandoned.

52 Us. (:1. 244/134 a 511 int. Cl 864d 15/04 581 Field of Search 244 134R, 134 B,

[56] References Cited UNITED STATES PATENTS 3,252,229 6/l966 Larson244/134 R 3,058,695 10/1962 Simonis... 244/134 R OTHER PUBLICATIONSFlight" Vol. 54, Aug. 26, '1948, pg. 239

BLFED AIR i .ENGINE.

Primary Examiner-Duane A. Reger Agsiqqnt xa mine r Greg ory W. O'ConnorAttorney-PafiTM; Craig, Jr., Charles E. Wands et al.

[ 5 7 ABSTRACT Anti-icing/de-icing apparatus for use in aircraft,comprising apertured fairings constructed from aluminum or alloysthereof defining air spaces therewithin, and means for deliveringtemperature controlled warm air under pressure to said air spaces, whichmeans includes a conduit for conveying engine bleed air to said airspaces, an inlet to the conduit for cool ambient air to be mixed withthe relatively warm engine bleed air, an anti-icing valve interposed inthe conduit between the engine bleed air intake and the ambient airinlet and control means for regulating the valve to maintain thepressure and temperature of the air delivered to the air spaces belowpredetermined nominal values, said control means includingpressure-responsive means and manually-controlled electrical means foroverriding the pressure-responsive means. Additionally, the presentinvention contemplates an emergency relief valve disposed in the conduitdownstream of the ambient air inlet and adapted to open in the eventthat the pressure or temperature of the air passing thereby is ofgreater than a predetermined maximum value.

13 Claims, 2 Drawing Figures SECONDARY MR INLET AIRCRAFT ANTI-ICINGAPPARATUS This is a continuation-in-part of my copending applicationSer. No. 885,503, filed Dec. 16, 1969, now

abandoned.

BACKGROUND OF THE INVENTION For some time, anti-icing apparatus employedin aircraft for preventing the formation of ice on faired surfaces hasutilized relatively warm engine bleed air and conduits for deliveringthis heated air, under pressure, to air spaces defined byapertured'fairings. With the ever-increasing demand for greater engineperformance, the conventional engine bleed air systems are distributingair at correspondingly greater temperatures and pressures.

Of course, the increase in engine performance cannot be effectivelyrealized unless the overall weight of the aircraft can be maintained atminimal levels. In view of the extremely high temperature and pressureof engine bleed air, however, it has been necessary to construct theapertured fairings from materials such as steel, which can withstand theexcessive temperature and pressure. The use of steel, however, for theconstruction of engine inlet fairings and the like, rather than lighteraluminum and aluminum alloys, has tended to increase the overallaircraft weight, thus detrimen-- tally affecting the aircraftperformance.

Thus, it is an object of the present invention to provide anti-icingapparatus utilizing the heated engine bleed air which can safely beemployed in conjunction with apertured fairings constructed fromaluminum or aluminum alloys.

Further, it is an object of the present invention to provide anti-icingapparatus of the type described hereinabove which utilizes relativelycool ambient air in conjunction with the relatively warm engine bleedair to maintain the pressure and temperature of the air delivered to thefaired surfaces within limits permitting the safe use of aluminum oraluminum alloys for the construction of the fairings.

It is still another object of the present invention to provideanti-icing apparatus of the type described above including a controlsystem adapted to automati-.

cally regulate the flow of engine bleed air automatically in response tothe pressure in the conduit upstream of the cool ambientairintake; a I

Still another object of the present invention resides in the provisionof a pilot-controlled override for selectively closing the conduit torestrict the flow therethrough of engine bleed air.

Another object of the present invention resides in the provision ofanti-icing apparatus of the type generally described hereinabove whichfurther includes an emer- SUMMARY OF THE INVENTION The foregoing objectsare accomplished, in accordance with the present invention, by theprovision of a conduit having an inlet for engine bleed air, a secondinlet for cool ambient air and an outlet to air distributing spacesdefined by apertured fairings preferably constructed from aluminum oralloys thereof. A valve, preferably of the common butterfly type, isdisposed within the conduit between the engine bleed airintake and theambient air inlet so as to be operable to selectively restrict the flowof engine bleed air to the outlet of the conduit.

An actuator is provided for selectively positioning the butterfly valvein response to a pressure signal from one of two alternate sources. Thefirst of these sources is a control device automatically responsive tothe pressure sensed in the conduit downstream of the butterfly valve andupstream of the ambient air intake. The second of the two alternatesources is a pilot-operated control device, preferably of the solenoidvalve type, arranged so as to produce a pressure signal sufficient tocause the actuator to move the butterfly valve to a closed positionirrespective of the condition of the pressure-responsive control device.

The present invention further contemplates a provision of an ejectornozzle within the conduit at the location of the ambient air intake toproduce a pumping effect, thus providing for effective mixing of theheated engine bleed air with the cool ambient air. Finally, an emergencyrelief valve is disposed within the conduit,

downstream of the ambient air intake, adapted to open in case the airflow thereby is at a pressure and/0r temperature in excess ofpredetermined maximum values, thus precluding damage of the fairingsconstructed from aluminum or alloys thereof. The emergency relief valveis adapted to lock in the open position and provide an indication of itsopen condition, thus signalling the pilot and alerting him to amalfunction of the control device.

BRIEF DESCRIPTION OF THE DRAWING The foregoing objects, features andadvantages of the present invention will become more readily apparentfrom the detailed description hereinbelow, when considered inconjunction with the accompanying drawing.

FIG. 1 is a schematic representation of the anti-icing apparatus and thecontrol system therefor; and

FIG. 2 is a detail sectional view of a relief valve used in theapparatus of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWING FIG. 1 is a schematic representationof a partial cross-sectional view of the inlet portion of a conventionaljet aircraft engine, incorporating the anti-icing apparatus contemplatedby the'present invention. For preventing the formation of ice on thefaired surfaces of the engine inlet, apertured fairings l are provided.The apertured fairings l are preferably constructed from aluminum or asimilarly light-weight alloy thereof. Fairings 1, together with sheetmetal members 2, which may also be constructed of aluminum or anotherlightweight metal, define therebetween air distributing spaces 3. I

A conduit generally designated by reference numeral 4 is provided forconveying warm air to air distributing spaces 3. Conduit 4 includes anengine bleed air inlet 5 wherein heated air is withdrawn from the engine6. Additionally, conduit 4 includes an inlet for cool ambient air 7 atthe inner end of a channel 8 which leads to an outer surface of theengine. At this outer surface, an air scoop 9 is disposed so as todeflect cool ambient air through channel 8 and inlet 7 into conduit 4.

In the region of inlet 7, an ejector nozzle 10 is provided, which servesas a pump. The mixing chamber (4A) effects a thorough and intimatemixing of the engine bleed air and secondary or ambient air.

A selectively-operable butterfly-type closure valve 11 is disposedwithin conduit 4 between engine bleed air inlet and secondary air inlet7. An actuator 12 is provided for effecting rotation of valve 11.

Actuator 12 includes a spring 13 normally biasing plunger 14 rearward(to the left, as viewed in the drawing), thus normally tending tomaintain valve 11 in an open position. From the opposite direction,plunger 14 may be acted upon, through diaphragm 16, by the pressure inchannel 15.

An automatic pressure-responsive control device 17 includes a diaphragm18 connected with a valve body 19. Diaphragm 18 is exposed, on one sidethereof, to the pressure P sensed downstream of valve 11 and upstream ofejector nozzle and transmitted to diaphragm 18 by means ofa channel 20.The opposite side of diaphragm 18 is acted upon by a spring 21, theforce of which is selected so as to yield when P, reaches a magnitude inexcess of a predetermined nominal level.

A solenoid-controlled valve 22 is arranged in communicating relationshipwith one side of diaphragm 16. The valve 22 includes a valve body 23movable between two seating positions 24 and 25. Under normalcircumstances, with the solenoid de-energized, valve body 23 assumes theposition illustrated, seated at valve seat 25. By activating a switch(not shown) provided, however, the pilot can cause the solenoid to beenergized, causes valve body 23 to seat at valve seat 24.

A normally closed emergency relief valve 26 is provided in conduit 4downstream of ambient air inlet 7 where mixing of the engine bleed airand the secondary air takes place. As seen in FIG. 2, the relief valve26, which may be of the poppet type, includes a poppet member 29 havinga generally hat-shaped configuration including a relatively flat endportion closed by a setscrew 30 which serves as the closure for theopening in conduit 4. The poppet 29 is supported for movement againstthe bias of a spring 31 within a guide member 34 which is secured to theconduit 4 by means of a plurality of bolts 33.

The poppet member 29 is provided with a plurality of holes, preferablythree holes, 29a in each of which a ball 27 is positioned. Each ball 27is held in position by the inner surface of the guide member 34 and thesurface of a resetting pin located within the guide memher and having anoperating end extending to the outside of the poppet member. The upperend of the resetting pin 28 has a cam surface 28a which is curved so asto bias the balls outwardly as the resetting pin is biased upwardly bythe force of spring 32. Thus, when the pressure P, of the air flowing inthe conduit exceeds a predetermined maximum, the poppet member 29 willbe forced downwardly against the bias of spring 31 and the balls 27 willbe translated to a position opposite a shoulder 34a on guide member 34where they can move outwardly in response to the urging of the camsurface 280 and thereby lock the poppet in the open position. Once theballs 27 are moved outwardly under shoulder 34a, the resetting pin willbe allowed to moved upwardly in response to spring 32 past the balls 27until it is stopped by the setscrew 30. This blocks the holes 29a andprevents the balls 27 from moving back inwardly, which the shoulder 340will have a tendency to do.

By having the relief valve 26 lock open, this serves as an indicationthat the control arrangement may have malfunctioned. To reset the reliefvalve one need only pull downwardly on the operating end of theresetting pin 28 against the bias of spring 32 to reposition the camsurface 280 adjacent the openings 29a, at which point the balls 27 willbe biased inwardly by the shoulder 34a and the force of spring 31,thereby unlocking the valve.

The operation of the' illustrated apparatus is as follows: under normaloperating conditions, with the pressure P, not exceeding a predeterminednominal level, valve body 19 remains seated in the position shown byvirtue of the force of spring 21. Thus, with the solenoid valve 22dc-energized, and valve body 23 seated, in the position illustrated, atvalve seat 25, no pressure is exerted upon diaphragm 16 to oppose theforce of spring 13 and valve 11 remains open.

If, however, the pressure P, rises to a level exceeding thepredetermined nominal level, then this pressure, transmitted via channel20, to one side of diaphragm 18, causes the diaphragm 18 to move despitethe force of spring 21 acting in opposition thereto. Thus, valve body 19will become unseated and the pressure P,, sensed at a position upstreamof valve 11 and transmitted through channels 27, 28, 29 and 15, will beexerted upon diaphragm 16 in opposition to the force exerted by spring13. Depending upon the magnitude of pressure P and the force of spring13, valve 11 may then be rotated to restrict, either partially ortotally, the flow of engine bleed air through conduit 4. With the flowof bleed air thus restricted, the pressure P should then stabilize,causing valve body 19 seek a position to maintain the necessary Ppressure on diaphragm 16 to stabilize valve 11 in the required position.

Independent of the relative pressure levels, solenoid valve 22 may beenergized by a switch provided, thus causing valve body 23 to be seatedat valve seat 24 rather than valve seat 25. Under such circumstances,the pressure P, will be exerted upon diaphragm 16 via channels 27 and15, thus causing valve 1 1 to be rotated into a closed position assumingthat the pressure P exerted upon diaphragm 16 exceeds the force ofspring 13.

Thus, it can clearly be seen that the present invention, utilizing coolambient air and effecting an intimate mixing thereof with relativelywarm engine bleed air, in combination with the novel control systemcontemplated, effectively limits the maximum pressure and temperature ofair delivered 'to the air distributing spaces 3. This facilitates theconstruction of fairings 1 from aluminum or other light-weight alloys,thus advantageously limiting the overall weight of the aircraft.

While the present invention has been disclosed with reference to but asingle embodiment, it is to be understood that the scope of theinvention is not limited to the details thereof, but is susceptible ofnumerous changes and modifications as would be apparent to one withnormal skill in the pertinent technology.

What is claimed is l. Anti-icing apparatus for use in aircraft,comprising:

apertured fairing means constructed from relatively light-weightmaterials, said fairing means defining air distribution spacestherewithin,

conduit means including first inlet means communieating with theaircraft engine for passage of engine bleed air there-through, secondinlet means disposed downstream of selectively operable valve means andcommunicating with an exterior surface of the aircraft for passage ofambient air therethrough, and outlet means communicating with said airdistribution spaces for delivery of air thereto,

said selectively-operable valve means being disposed within said conduitmeans between said first inlet means and said second inlet means,control means responsive to the pressure within said conduit meansupstream of said second inlet means and including actuating meansfor'actuating said valve means to selectively restrict the flow of saidengine bleed air in response to the pressure within said conduit meansupstream of said valve means, and

emergency relief valve means disposed in said conduit means donwstreamof said second inlet means for preventing air flow to said airdistribution spaces at pressure levels in excess of predeterminedmaximum levels.

2. Anti-icing apparatus according to-claim 1, wherein said emergencyrelief valve means is disposed between said second inlet means and saidoutlet means, said relief valve means being of the normally-closed type.

3. Anti-icing apparatus according to claim 2, wherein said emergencyrelief valve means includes means for locking said valve means in theopen position thereby indicating the open position of said valve means.

4. Anti-icing apparatus for use in aircraft, comprising:

apertured fairing means constructed from relatively light-weightmaterials, said fairing means defining air distribution spacestherewithin,

conduit'means including first inlet means communicating with theaircraft engine for passage of engine bleed air therethrough, secondinlet means disposed downstream of selectively operable valve means andcommunicating with an exterior surface of the aircraft for passage ofambient air therethrough, and outlet means communicating with said airdistribution spaces for delivery of air thereto, i saidselectively-operable valve means being disposed within said conduitmeans between said first inlet means and said second inlet means,control means responsive to the pressure within said 1 conduitmeansfupstream of said second inlet means and including actuating meansfor actuating said valve means to selectively restrict the flow of saidengine bleed air in response to the pressure within said conduit meansupstream of said valve means,v

and wherein said control means further includes selectively energizablesolenoid valve means, said solenoid valve means being operable, whenenergized, to cause said actuating means to actuate said firstmentionedvalve'means to restrict the flow of said engine bleed air. I g 5.Anti-icing apparatus according to claim 4, further comprising emergencyrelief valve means disposed in said conduit means downstream of saidsecond inlet means for preventing air flow tosaid air distributionspaces at temperature and pressure levels in excess of predeterminedmaximum levels.

6. Anti-icing apparatus for use in aircraft, comprising:

apertured fairing means constructed from relatively light-weightmaterials, said fairing means defining air distribution spacestherewithin, conduit means including first inlet means communicatingwith the aircraft engine for passage of engine bleed air therethrough,second inlet means disposed downstream of selectively operable valvemeans and communicating with an exterior surface of the aircraft forpassage of ambient air therethrough, and outlet means communicating withsaid air distribution spaces for delivery of air thereto, saidselectively-operable valve means being disposed within said conduitmeans between said first inlet means and said second inlet means,

control means responsive to the pressure within said conduit meansupstream of said second inlet means and including actuating means foractuating said valve means to selectively restrict the flow of saidengine bleed air in response to the pressure within said conduit meansupstream of said valve'means, and

wherein said control means further includes pressure-responsive valvemeans operable to communicate a pressure signal to said actuating meansto cause same to actuate said first-mentioned valve means to restrictthe flow of engine bleed air when the pressure sensed within saidconduit means at a point between said valve means and said second inletmeans reaches a level in excess of a predetermined nominal value.

7. Anti-icing apparatus according to claim 6, wherein saidpressure-responsive valve means includes diaphragm means exposed, on oneside thereof, to the sensed pressure in said conduit means between saidfirst-mentioned valve means and said second inlet means and, on theother side, to a spring means exerting a force of predeterminedmagnitude.

8. Anti-icingapparatus according to claim 7, wherein said actuatingmeans includes a diaphragm means exposed, on one side thereof, to apressure signal selectively transmitted by said pressure-responsivevalve means and, on the other side thereof, to a spring means exerting aforce of a predetermined magnitudefwhich force tends to cause saidfirst-mentioned valve means to permit free flow of engine bleed air inthe absence of an opposed balancing pressure signal exerted upon saiddiaphragm means. I

9. Anti-icing apparatus according to claim 8, wherein said control meansfurther includes pressure channel means operatively connecting saidconduit means, at a point upstream of said first-mentioned valve means,with one side of said diaphragm means of said actuating means, saidpressure-responsive valve means being operable to selectively block saidpressure channel means when said sensed pressure in said conduit meansat a point between said valve means and said second inlet means is oflesser magnitude than said predetermined nominal value.

10. Anti-icing apparatus according to claim 9, wherein said controlmeans further includes selectively energizable solenoid valve meansoperable, when deenergized, to block parallel pressure channel meansoperatively connecting said conduit means, at a point upstream of saidfirst-mentioned valve means, with said one side of said diaphragm meansof said actuating means and to open said parallel pressure channel meanswhen said solenoid valve means is energized, irrespective of thecondition of said pressure-responsive valve means.

11. Anti-icing apparatus according to claim 10, wherein said aperturedfairing means are constructed from aluminum or alloys thereof.

12. Anti-icing apparatus according to claim 10, further comprisingemergency relief valve means disposed between said conduit means, at apoint downstream of said second inletmeans, and said outlet means, saidremeans.

* :r s s x

1. Anti-icing apparatus for use in aircraft, comprising: aperturedfairing means constructed from relatively light-weight materials, saidfairing means defining air distribution spaces therewithin, conduitmeans including first inlet means communicating with the aircraft enginefor passage of engine bleed air there-through, second inlet meansdisposed downstream of selectively operable valve means andcommunicating with an exterior surface of the aircraft for passage ofambient air therethrough, and outlet means communicating with said airdistribution spaces for delivery of air thereto, saidselectively-operable valve means being disposed within said conduitmeans between said first inlet means and said second inlet means,control means responsive to the pressure within said conduit meansupstream of said second inlet means and including actuating means foractuating said valve means to selectively restrict the flow of saidengine bleed air in response to the pressure within said conduit meansupstream of said valve means, and emergency relief valve means disposedin said conduit means donwstream of said second inlet means forpreventing air flow to said air distribution spaces at pressure levelsin excess of predetermined maximum levels.
 2. Anti-icing apparatusaccording to claim 1, wherein said emergency relief valve means isdisposed between said second inlet means and said outlet means, saidrelief valve means being of the normally-closed type.
 3. Anti-icingapparatus according to claim 2, wherein said emergency relief valvemeans includes means for locking said valve means in the open positionthereby indicating the open position of said valve means.
 4. Anti-icingapparatus for use in aircraft, comprising: apertured fairing meansconstructed from relatively light-weight materials, said fairing meansdefining air distribution spaces therewithin, conduit means includingfirst inlet means communicating with the aircraft engine for passage ofengine bleed air therethrough, second inlet means disposed downstream ofselectively operable valve means and communicating with an exteriorsurface of the aircraft for passage of ambient air therethrough, andoutlet means communicating with said air distribution spaces fordelivery of air thereto, said selectively-operable valve means beingdisposed within said conduit means between said first inlet means andsaid second inlet means, control means responsive to the pressure withinsaid conduit means upstream of said second inlet means and includingactuating means for actuating said valve means to selectively restrictthe flow of said engine bleed air in response to the pressure withinsaid conduit means upstream of said valve means, and wherein saidcontrol means further includes selectively energizable solenoid valvemeans, said solenoid valve means being operable, when energized, tocause said actuating means to actuate said first-mentioned valve meansto restrict the flow of said engine bleed air.
 5. Anti-icing apparatusaccording to claim 4, further comprising emergency relief valve meansdisposed in said conduit means downstream of said second inlet means forpreventing air flow to said air distribution spaces at temperature andpressure levels in excess of predetermined maximum levels.
 6. Anti-icingapparatus for use in aircraft, comprising: apertured fairing meansconstructed from relatively light-weight materials, said fairing meansdefining air distribution spaces therewithin, conduit means includingfirst inlet means communicating with the aircraft engine for passage ofengine bleed air therethrough, second inlet means disposed downstream ofselectively operable valve means and communicating with an exteriorsurface of the aircraft for passage of ambient air therethrough, andoutlet means communicating with said air distribution spaces fordelivery of air thereto, said selectively-operable valve means beingdisposed within said conduit means between said first inlet means andsaid second inlet means, control means responsive to the pressure withinsaid conduit means upstream of said second inlet means and includingactuating means for actuating said valve means to selectively restrictthe flow of said engine bleed air in response to the pressure withinsaid conduit means upstream of said valve means, and wherein saidcontrol means further includes pressure-responsive valve means operableto communicate a pressure signal to said actuating means to cause sameto actuate said first-mentioned valve means to restrict the flow ofengine bleed air when the pressure sensed within said conduit means at apoint between said valve means and said second inlet means reaches alevel in excess of a predetermined nominal value.
 7. Anti-icingapparatus according to claim 6, wherein said pressure-responsive valvemeans includes diaphragm meanS exposed, on one side thereof, to thesensed pressure in said conduit means between said first-mentioned valvemeans and said second inlet means and, on the other side, to a springmeans exerting a force of predetermined magnitude.
 8. Anti-icingapparatus according to claim 7, wherein said actuating means includes adiaphragm means exposed, on one side thereof, to a pressure signalselectively transmitted by said pressure-responsive valve means and, onthe other side thereof, to a spring means exerting a force of apredetermined magnitude, which force tends to cause said first-mentionedvalve means to permit free flow of engine bleed air in the absence of anopposed balancing pressure signal exerted upon said diaphragm means. 9.Anti-icing apparatus according to claim 8, wherein said control meansfurther includes pressure channel means operatively connecting saidconduit means, at a point upstream of said first-mentioned valve means,with one side of said diaphragm means of said actuating means, saidpressure-responsive valve means being operable to selectively block saidpressure channel means when said sensed pressure in said conduit meansat a point between said valve means and said second inlet means is oflesser magnitude than said predetermined nominal value.
 10. Anti-icingapparatus according to claim 9, wherein said control means furtherincludes selectively energizable solenoid valve means operable, whende-energized, to block parallel pressure channel means operativelyconnecting said conduit means, at a point upstream of saidfirst-mentioned valve means, with said one side of said diaphragm meansof said actuating means and to open said parallel pressure channel meanswhen said solenoid valve means is energized, irrespective of thecondition of said pressure-responsive valve means.
 11. Anti-icingapparatus according to claim 10, wherein said apertured fairing meansare constructed from aluminum or alloys thereof.
 12. Anti-icingapparatus according to claim 10, further comprising emergency reliefvalve means disposed between said conduit means, at a point downstreamof said second inlet means, and said outlet means, said relief valvemeans being normally-closed, but operable to open when the air flowthereby is at pressure levels in excess of predetermined maximum values,thus precluding air flow to said air distribution spaces which might bedestructive of said fairing means.
 13. Anti-icing apparatus according toclaim 12, wherein said emergency relief valve means includes means forlocking said valve means in the open position thereby indicating theopen position of said valve means.